1. Field of the Invention
The present invention relates to a portable information terminal suitable for use in a handset of a radio telephone apparatus and so on.
2. Description of the Related Art
Various proposed casings of the portable information terminal such as a radio telephone apparatus, a portable telephone apparatus or the like are arranged so as to be convenient in portability.
FIG. 1 is a perspective view showing a portable telephone apparatus which is not being used for communication. FIG. 2 is a perspective view showing the portable telephone apparatus which is being used for communication.
In FIGS. 1 and 2, a portable telephone set 1 is formed of a body casing 2 and a card casing (sub casing) 3.
The body casing 2 has a shape of a substantially rectangular parallelepiped. As shown in FIG. 2, the body casing 2 has a step portion 4 and a thickness of a lower-side portion 2b of the body casing 2 is less than that of an upper-side portion 2a thereof. A panel 5 having an operation key group 6 for a telephone such as a ten key or the like is provided on a front surface of the lower-side portion 2b. A hook switch 7 is provided on the panel 5.
The upper-side portion 2a of the body casing 2 incorporates a receiver 8 therein. The receiver 8 emanates a dial tone through apertures 9 provided through the body casing 2. A power source key 10 is provided on a front surface of the upper-side portion 2a. An antenna 11 can be inserted in the body casing 2 and is drawn therefrom upon a telephone call as shown in FIG. 2.
The card casing 3 incorporating a transmitter 13 is pivotally fitted to a lower end edge portion of the body casing 2 by a hinge portion 12. The back surface of the card casing 3 merely functions as a cover in a state that the card casing 3 is rotated around the hinge portion 12 and closed so as to be opposed to the panel 5 of the body casing 2 as shown in FIG. 1. On the other hand, in a state that the card casing 3 is rotated around the hinge portion 12 and opened as shown in FIG. 2, a user can make a telephone call by speaking toward the transmitter 13 through apertures 14 formed through a transmitter-side surface of the card casing 3.
According to the portable telephone apparatus having the above arrangement, it is possible to make the portable telephone apparatus compact when the user carries it, and it is possible to realize an arrangement which provides convenience in portability. However, since the portable telephone apparatus is used upon a telephone call with the card casing 3 being rotated around the hinge portion 12 and opened as shown in FIG. 2, the card casing 3 is not stable, is easily broken, and may come off from the body casing 2, which leads to inconvenience in use thereof.
Moreover, there is then the problem that when the user makes a telephone call, the body casing 2 and the opened card casing 3 occupy a considerable space or area and hence the whole of the portable telephone apparatus becomes large-sized.